Rach configurations for nr shared spectrum

ABSTRACT

Random access channel (RACH) configurations for new radio (NR) shared spectrum (NR-SS) networks are disclosed. A base station may perform a listen before talk (LBT) procedure on a shared communication channel at a beginning of a discovery measurement timing configuration (DMTC) window. In response to a successful LBT, the base station may transmit synchronization signals over a plurality of directional beams according to a predetermined sequence. The user equipment (UE) may determine the predetermined sequence through the detected synchronization signals. The base station may signal configuration of additional random access resources when the LBT procedure delays beyond dedicated random access resources. The base station may then monitor for UEs to transmit random access signals from each direction corresponding to directional beams within the additional random access resources according to the predetermined sequence.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 62/538,466, entitled, “RACH CONFIGURATIONS FOR NR SHAREDSPECTRUM,” filed on Jul. 28, 2017, which is expressly incorporated byreference herein in its entirety.

BACKGROUND Field

Aspects of the present disclosure relate generally to wirelesscommunication systems and to random access channel (RACH) configurationsfor new radio (NR) shared spectrum networks.

Background

Wireless communication networks are widely deployed to provide variouscommunication services such as voice, video, packet data, messaging,broadcast, and the like. These wireless networks may be multiple-accessnetworks capable of supporting multiple users by sharing the availablenetwork resources. Such networks, which are usually multiple accessnetworks, support communications for multiple users by sharing theavailable network resources. One example of such a network is theUniversal Terrestrial Radio Access Network (UTRAN). The UTRAN is theradio access network (RAN) defined as a part of the Universal MobileTelecommunications System (UMTS), a third generation (3G) mobile phonetechnology supported by the 3rd Generation Partnership Project (3GPP).Examples of multiple-access network formats include Code DivisionMultiple Access (CDMA) networks, Time Division Multiple Access (TDMA)networks, Frequency Division Multiple Access (FDMA) networks, OrthogonalFDMA (OFDMA) networks, and Single-Carrier FDMA (SC-FDMA) networks.

A wireless communication network may include a number of base stationsor node Bs that can support communication for a number of userequipments (UEs). A UE may communicate with a base station via downlinkand uplink. The downlink (or forward link) refers to the communicationlink from the base station to the UE, and the uplink (or reverse link)refers to the communication link from the UE to the base station.

A base station may transmit data and control information on the downlinkto a UE and/or may receive data and control information on the uplinkfrom the UE. On the downlink, a transmission from the base station mayencounter interference due to transmissions from neighbor base stationsor from other wireless radio frequency (RF) transmitters. On the uplink,a transmission from the UE may encounter interference from uplinktransmissions of other UEs communicating with the neighbor base stationsor from other wireless RF transmitters. This interference may degradeperformance on both the downlink and uplink.

As the demand for mobile broadband access continues to increase, thepossibilities of interference and congested networks grows with more UEsaccessing the long-range wireless communication networks and moreshort-range wireless systems being deployed in communities. Research anddevelopment continue to advance wireless technologies not only to meetthe growing demand for mobile broadband access, but to advance andenhance the user experience with mobile communications.

SUMMARY

In one aspect of the disclosure, a method of wireless communicationincludes performing, by a base station, a listen before talk (LBT)procedure on a shared communication channel at a beginning of adiscovery measurement timing configuration (DMTC) window, transmitting,by the base station, synchronization signals on the shared communicationchannel in response to success of the LBT procedure, wherein thesynchronization signals are transmitted over a plurality of directionalbeams according to a predetermined sequence, signaling, by the basestation, configuration of additional random access resources in responseto the LBT procedure delaying beyond dedicated random access resources,and monitoring, by the base station, for random access signals from eachdirection corresponding to the plurality of directional beams within theadditional random access resources, wherein the monitoring monitors theeach direction according to the predetermined sequence.

In an additional aspect of the disclosure, a method of wirelesscommunication includes obtaining, by a user equipment (UE), a firstlocation of dedicated random access resources on a shared communicationchannel, monitoring, by the UE, for a plurality of synchronizationsignals within a DMTC window, wherein the plurality of synchronizationsignals are received on a plurality of directional beams in a beamsequence, receiving, by the UE, configuration of additional randomaccess resources outside of the DMTC window, and transmitting, by theUE, a random access signal on one of the plurality of directional beamsafter completing a successful LBT procedure on the shared communicationchannel, wherein the transmitting is performed according to the beamsequence on the additional random access resources.

In an additional aspect of the disclosure, an apparatus configured forwireless communications includes means for performing, by a basestation, a LBT procedure on a shared communication channel at abeginning of a DMTC window, means for transmitting, by the base station,synchronization signals on the shared communication channel in responseto success of the LBT procedure, wherein the synchronization signals aretransmitted over a plurality of directional beams according to apredetermined sequence, means for signaling, by the base station,configuration of additional random access resources in response to theLBT procedure delaying beyond dedicated random access resources, andmeans for monitoring, by the base station, for random access signalsfrom each direction corresponding to the plurality of directional beamswithin the additional random access resources, wherein the means formonitoring monitors the each direction according to the predeterminedsequence.

In an additional aspect of the disclosure, an apparatus configured forwireless communications includes means for obtaining, by a UE, a firstlocation of dedicated random access resources on a shared communicationchannel, means for monitoring, by the UE, for a plurality ofsynchronization signals within a DMTC window, wherein the plurality ofsynchronization signals are received on a plurality of directional beamsin a beam sequence, means for receiving, by the UE, configuration ofadditional random access resources outside of the DMTC window, and meansfor transmitting, by the UE, a random access signal on one of theplurality of directional beams after completing a successful LBTprocedure on the shared communication channel, wherein the means fortransmitting is performed according to the beam sequence on theadditional random access resources.

In an additional aspect of the disclosure, a non-transitorycomputer-readable medium having program code recorded thereon. Theprogram code further includes code to perform, by a base station, a LBTprocedure on a shared communication channel at a beginning of a DMTCwindow, code to transmit, by the base station, synchronization signalson the shared communication channel in response to success of the LBTprocedure, wherein the synchronization signals are transmitted over aplurality of directional beams according to a predetermined sequence,code to signal, by the base station, configuration of additional randomaccess resources in response to the LBT procedure delaying beyonddedicated random access resources, and code to monitor, by the basestation, for random access signals from each direction corresponding tothe plurality of directional beams within the additional random accessresources, wherein the code to monitor monitors the each directionaccording to the predetermined sequence.

In an additional aspect of the disclosure, a non-transitorycomputer-readable medium having program code recorded thereon. Theprogram code further includes code to obtain, by a UE, a first locationof dedicated random access resources on a shared communication channel,code to monitor, by the UE, for a plurality of synchronization signalswithin a DMTC window, wherein the plurality of synchronization signalsare received on a plurality of directional beams in a beam sequence,code to receive, by the UE, configuration of additional random accessresources outside of the DMTC window, and code to transmit, by the UE, arandom access signal on one of the plurality of directional beams aftercompleting a successful LBT procedure on the shared communicationchannel, wherein the code to transmit is performed according to the beamsequence on the additional random access resources.

In an additional aspect of the disclosure, an apparatus configured forwireless communication is disclosed. The apparatus includes at least oneprocessor, and a memory coupled to the processor. The processor isconfigured to perform, by a base station, a LBT procedure on a sharedcommunication channel at a beginning of a DMTC window, to transmit, bythe base station, synchronization signals on the shared communicationchannel in response to success of the LBT procedure, wherein thesynchronization signals are transmitted over a plurality of directionalbeams according to a predetermined sequence, to signal, by the basestation, configuration of additional random access resources in responseto the LBT procedure delaying beyond dedicated random access resources,and code to monitor, by the base station, for random access signals fromeach direction corresponding to the plurality of directional beamswithin the additional random access resources, wherein the configurationto monitor monitors the each direction according to the predeterminedsequence.

In an additional aspect of the disclosure, an apparatus configured forwireless communication is disclosed. The apparatus includes at least oneprocessor, and a memory coupled to the processor. The processor isconfigured to obtain, by a UE, a first location of dedicated randomaccess resources on a shared communication channel, to monitor, by theUE, for a plurality of synchronization signals within a DMTC window,wherein the plurality of synchronization signals are received on aplurality of directional beams in a beam sequence, to receive, by theUE, configuration of additional random access resources outside of theDMTC window, and to transmit, by the UE, a random access signal on oneof the plurality of directional beams after completing a successful LBTprocedure on the shared communication channel, wherein the configurationto transmit is performed according to the beam sequence on theadditional random access resources.

The foregoing has outlined rather broadly the features and technicaladvantages of examples according to the disclosure in order that thedetailed description that follows may be better understood. Additionalfeatures and advantages will be described hereinafter. The conceptionand specific examples disclosed may be readily utilized as a basis formodifying or designing other structures for carrying out the samepurposes of the present disclosure. Such equivalent constructions do notdepart from the scope of the appended claims. Characteristics of theconcepts disclosed herein, both their organization and method ofoperation, together with associated advantages will be better understoodfrom the following description when considered in connection with theaccompanying figures. Each of the figures is provided for the purpose ofillustration and description, and not as a definition of the limits ofthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentdisclosure may be realized by reference to the following drawings. Inthe appended figures, similar components or features may have the samereference label. Further, various components of the same type may bedistinguished by following the reference label by a dash and a secondlabel that distinguishes among the similar components. If just the firstreference label is used in the specification, the description isapplicable to any one of the similar components having the same firstreference label irrespective of the second reference label.

FIG. 1 is a block diagram illustrating details of a wirelesscommunication system.

FIG. 2 is a block diagram illustrating a design of a base station and aUE configured according to one aspect of the present disclosure.

FIG. 3 is a block diagram illustrating a wireless communication systemincluding base stations that use directional wireless beams.

FIGS. 4A and 4B are block diagrams illustrating example blocks accordingto one aspect of the present disclosure.

FIG. 5 is a block diagram illustrating a base station and UE configuredaccording to one aspect of the present disclosure.

FIG. 6 is a block diagram illustrating a base station and UE configuredaccording to one aspect of the present disclosure.

FIG. 7 is a block diagram illustrating a base station and UE configuredaccording to one aspect of the present disclosure.

FIG. 8 is a block diagram illustrating an example base stationconfigured according to one aspect of the present disclosure.

FIG. 9 is a block diagram illustrating an example UE configuredaccording to one aspect of the present disclosure.

DETAILED DESCRIPTION

The detailed description set forth below, in connection with theappended drawings, is intended as a description of variousconfigurations and is not intended to limit the scope of the disclosure.Rather, the detailed description includes specific details for thepurpose of providing a thorough understanding of the inventive subjectmatter. It will be apparent to those skilled in the art that thesespecific details are not required in every case and that, in someinstances, well-known structures and components are shown in blockdiagram form for clarity of presentation.

This disclosure relates generally to providing or participating inauthorized shared access between two or more wireless communicationssystems, also referred to as wireless communications networks. Invarious embodiments, the techniques and apparatus may be used forwireless communication networks such as code division multiple access(CDMA) networks, time division multiple access (TDMA) networks,frequency division multiple access (FDMA) networks, orthogonal FDMA(OFDMA) networks, single-carrier FDMA (SC-FDMA) networks, LTE networks,GSM networks, 5^(th) Generation (5G) or new radio (NR) networks, as wellas other communications networks. As described herein, the terms“networks” and “systems” may be used interchangeably.

An OFDMA network may implement a radio technology such as evolved UTRA(E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, flash-OFDM and thelike. UTRA, E-UTRA, and Global System for Mobile Communications (GSM)are part of universal mobile telecommunication system (UMTS). Inparticular, long term evolution (LTE) is a release of UMTS that usesE-UTRA. UTRA, E-UTRA, GSM, UMTS and LTE are described in documentsprovided from an organization named “3rd Generation Partnership Project”(3GPP), and cdma2000 is described in documents from an organizationnamed “3rd Generation Partnership Project 2” (3GPP2). These variousradio technologies and standards are known or are being developed. Forexample, the 3rd Generation Partnership Project (3GPP) is acollaboration between groups of telecommunications associations thataims to define a globally applicable third generation (3G) mobile phonespecification. 3GPP long term evolution (LTE) is a 3GPP project whichwas aimed at improving the universal mobile telecommunications system(UMTS) mobile phone standard. The 3GPP may define specifications for thenext generation of mobile networks, mobile systems, and mobile devices.The present disclosure is concerned with the evolution of wirelesstechnologies from LTE, 4G, 5G, NR, and beyond with shared access towireless spectrum between networks using a collection of new anddifferent radio access technologies or radio air interfaces.

In particular, 5G networks contemplate diverse deployments, diversespectrum, and diverse services and devices that may be implemented usingan OFDM-based unified, air interface. In order to achieve these goals,further enhancements to LTE and LTE-A are considered in addition todevelopment of the new radio technology for 5G NR networks. The 5G NRwill be capable of scaling to provide coverage (1) to a massive Internetof things (IoTs) with an ultra-high density (e.g., ˜1 M nodes/km²),ultra-low complexity (e.g., ˜10s of bits/sec), ultra-low energy (e.g.,˜10+ years of battery life), and deep coverage with the capability toreach challenging locations; (2) including mission-critical control withstrong security to safeguard sensitive personal, financial, orclassified information, ultra-high reliability (e.g., ˜99.9999%reliability), ultra-low latency (e.g., ˜1 ms), and users with wideranges of mobility or lack thereof; and (3) with enhanced mobilebroadband including extreme high capacity (e.g., ˜10 Tbps/km²), extremedata rates (e.g., multi-Gbps rate, 100+ Mbps user experienced rates),and deep awareness with advanced discovery and optimizations.

The 5G NR may be implemented to use optimized OFDM-based waveforms withscalable numerology and transmission time interval (TTI); having acommon, flexible framework to efficiently multiplex services andfeatures with a dynamic, low-latency time division duplex(TDD)/frequency division duplex (FDD) design; and with advanced wirelesstechnologies, such as massive multiple input, multiple output (MIMO),robust millimeter wave (mmWave) transmissions, advanced channel coding,and device-centric mobility. Scalability of the numerology in 5G NR,with scaling of subcarrier spacing, may efficiently address operatingdiverse services across diverse spectrum and diverse deployments. Forexample, in various outdoor and macro coverage deployments of less than3 GHz FDD/TDD implementations, subcarrier spacing may occur with 15 kHz,for example over 1, 5, 10, 20 MHz, and the like bandwidth. For othervarious outdoor and small cell coverage deployments of TDD greater than3 GHz, subcarrier spacing may occur with 30 kHz over 80/100 MHzbandwidth. For other various indoor wideband implementations, using aTDD over the unlicensed portion of the 5 GHz band, the subcarrierspacing may occur with 60 kHz over a 160 MHz bandwidth. Finally, forvarious deployments transmitting with mmWave components at a TDD of 28GHz, subcarrier spacing may occur with 120 kHz over a 500 MHz bandwidth.

The scalable numerology of the 5G NR facilitates scalable TTI fordiverse latency and quality of service (QoS) requirements. For example,shorter TTI may be used for low latency and high reliability, whilelonger TTI may be used for higher spectral efficiency. The efficientmultiplexing of long and short TTIs to allow transmissions to start onsymbol boundaries. 5G NR also contemplates a self-contained integratedsubframe design with uplink/downlink scheduling information, data, andacknowledgement in the same subframe. The self-contained integratedsubframe supports communications in unlicensed or contention-basedshared spectrum, adaptive uplink/downlink that may be flexiblyconfigured on a per-cell basis to dynamically switch between uplink anddownlink to meet the current traffic needs.

Various other aspects and features of the disclosure are furtherdescribed below. It should be apparent that the teachings herein may beembodied in a wide variety of forms and that any specific structure,function, or both being disclosed herein is merely representative andnot limiting. Based on the teachings herein one of an ordinary level ofskill in the art should appreciate that an aspect disclosed herein maybe implemented independently of any other aspects and that two or moreof these aspects may be combined in various ways. For example, anapparatus may be implemented or a method may be practiced using anynumber of the aspects set forth herein. In addition, such an apparatusmay be implemented or such a method may be practiced using otherstructure, functionality, or structure and functionality in addition toor other than one or more of the aspects set forth herein. For example,a method may be implemented as part of a system, device, apparatus,and/or as instructions stored on a computer readable medium forexecution on a processor or computer. Furthermore, an aspect maycomprise at least one element of a claim.

FIG. 1 is a block diagram illustrating 5G network 100 including variousbase stations and UEs configured according to aspects of the presentdisclosure. The 5G network 100 includes a number of base stations 105and other network entities. A base station may be a station thatcommunicates with the UEs and may also be referred to as an evolved nodeB (eNB), a next generation eNB (gNB), an access point, and the like.Each base station 105 may provide communication coverage for aparticular geographic area. In 3GPP, the term “cell” can refer to thisparticular geographic coverage area of a base station and/or a basestation subsystem serving the coverage area, depending on the context inwhich the term is used.

A base station may provide communication coverage for a macro cell or asmall cell, such as a pico cell or a femto cell, and/or other types ofcell. A macro cell generally covers a relatively large geographic area(e.g., several kilometers in radius) and may allow unrestricted accessby UEs with service subscriptions with the network provider. A smallcell, such as a pico cell, would generally cover a relatively smallergeographic area and may allow unrestricted access by UEs with servicesubscriptions with the network provider. A small cell, such as a femtocell, would also generally cover a relatively small geographic area(e.g., a home) and, in addition to unrestricted access, may also providerestricted access by UEs having an association with the femto cell(e.g., UEs in a closed subscriber group (CSG), UEs for users in thehome, and the like). A base station for a macro cell may be referred toas a macro base station. A base station for a small cell may be referredto as a small cell base station, a pico base station, a femto basestation or a home base station. In the example shown in FIG. 1, the basestations 105 d and 105 e are regular macro base stations, while basestations 105 a-105 c are macro base stations enabled with one of 3dimension (3D), full dimension (FD), or massive MIMO. Base stations 105a-105 c take advantage of their higher dimension MIMO capabilities toexploit 3D beamforming in both elevation and azimuth beamforming toincrease coverage and capacity. Base station 105 f is a small cell basestation which may be a home node or portable access point. A basestation may support one or multiple (e.g., two, three, four, and thelike) cells.

The 5G network 100 may support synchronous or asynchronous operation.For synchronous operation, the base stations may have similar frametiming, and transmissions from different base stations may beapproximately aligned in time. For asynchronous operation, the basestations may have different frame timing, and transmissions fromdifferent base stations may not be aligned in time.

The UEs 115 are dispersed throughout the wireless network 100, and eachUE may be stationary or mobile. A UE may also be referred to as aterminal, a mobile station, a subscriber unit, a station, or the like. AUE may be a cellular phone, a personal digital assistant (PDA), awireless modem, a wireless communication device, a handheld device, atablet computer, a laptop computer, a cordless phone, a wireless localloop (WLL) station, or the like. In one aspect, a UE may be a devicethat includes a Universal Integrated Circuit Card (UICC). In anotheraspect, a UE may be a device that does not include a UICC. In someaspects, UEs that do not include UICCs may also be referred to asinternet of everything (IoE) devices. UEs 115 a-115 d are examples ofmobile smart phone-type devices accessing 5G network 100. A UE may alsobe a machine specifically configured for connected communication,including machine type communication (MTC), enhanced MTC (eMTC),narrowband IoT (NB-IoT) and the like. UEs 115 e-115 k are examples ofvarious machines configured for communication that access 5G network100. A UE may be able to communicate with any type of the base stations,whether macro base station, small cell, or the like. In FIG. 1, alightning bolt (e.g., communication links) indicates wirelesstransmissions between a UE and a serving base station, which is a basestation designated to serve the UE on the downlink and/or uplink, ordesired transmission between base stations, and backhaul transmissionsbetween base stations.

In operation at 5G network 100, base stations 105 a-105 c serve UEs 115a and 115 b using 3D beamforming and coordinated spatial techniques,such as coordinated multipoint (CoMP) or multi-connectivity. Macro basestation 105 d performs backhaul communications with base stations 105a-105 c, as well as small cell, base station 105 f. Macro base station105 d also transmits multicast services which are subscribed to andreceived by UEs 115 c and 115 d. Such multicast services may includemobile television or stream video, or may include other services forproviding community information, such as weather emergencies or alerts,such as Amber alerts or gray alerts.

5G network 100 also support mission critical communications withultra-reliable and redundant links for mission critical devices, such UE115 e, which is a drone. Redundant communication links with UE 115 einclude from macro base stations 105 d and 105 e, as well as small cellbase station 105 f. Other machine type devices, such as UE 115 f(thermometer), UE 115 g (smart meter), and UE 115 h (wearable device)may communicate through 5G network 100 either directly with basestations, such as small cell base station 105 f, and macro base station105 e, or in multi-hop configurations by communicating with another userdevice which relays its information to the network, such as UE 115 fcommunicating temperature measurement information to the smart meter, UE115 g, which is then reported to the network through small cell basestation 105 f. 5G network 100 may also provide additional networkefficiency through dynamic, low-latency TDD/FDD communications, such asin a vehicle-to-vehicle (V2V) mesh network between UEs 115 i-115 kcommunicating with macro base station 105 e.

In operations of 5G network 100 using a new radio (NR) implementation,multiple network nodes may each share access to allocated communicationchannels, both between multiple nodes of the same network operator, butalso between nodes of different network operators. The random accessprocess may be affected due to the indefinite transmission aspects oflisten before talk (LBT) procedures. Physical random access channel(PRACH) information may be provided by each network operator in systeminformation broadcast over the air. Both NR synchronization signals andPRACH transmissions maybe subject to LBT procedures. Thus, for example,base stations 105 a-105 c would each perform LBT prior to transmissionof any NR synchronization signals or transmission of PRACH information.When subject to LBT, the PRACH information may not be available at theexpected location.

According to aspects of the present disclosure, base stations 105 a-105c may perform the LBT procedure at the beginning of a discoverymeasurement timing configuration (DMTC) window. If a successful LBT isdetected by either of base stations 105 a-105 c, NR synchronizationsignals may be transmitted in a predetermined sequence of beamdirections. Where the LBT procedure is not determined until afterdedicated RACH resources, any of base stations 105 a-105 c may signalconfiguration of additional RACH resources. Depending on the directionfrom which either of UEs 115 a and 115 b respond to the synchronizationsignals, the corresponding transmitting nodes of base stations 105 a-105c would monitor for RACH signals from each of the beam directions itused for transmitting the synchronization signals within the additionalRACH resources configured. The corresponding one of base stations 105a-105 c would perform this monitoring according to the same sequenceused for transmitting the synchronization signals.

FIG. 2 shows a block diagram of a design of a base station 105 and a UE115, which may be one of the base station and one of the UEs in FIG. 1.At the base station 105, a transmit processor 220 may receive data froma data source 212 and control information from a controller/processor240. The control information may be for the PBCH, PCFICH, PHICH, PDCCH,EPDCCH, MPDCCH etc. The data may be for the PDSCH, etc. The transmitprocessor 220 may process (e.g., encode and symbol map) the data andcontrol information to obtain data symbols and control symbols,respectively. The transmit processor 220 may also generate referencesymbols, e.g., for the PSS, SSS, and cell-specific reference signal. Atransmit (TX) multiple-input multiple-output (MIMO) processor 230 mayperform spatial processing (e.g., precoding) on the data symbols, thecontrol symbols, and/or the reference symbols, if applicable, and mayprovide output symbol streams to the modulators (MODs) 232 a through 232t. Each modulator 232 may process a respective output symbol stream(e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator232 may further process (e.g., convert to analog, amplify, filter, andupconvert) the output sample stream to obtain a downlink signal.Downlink signals from modulators 232 a through 232 t may be transmittedvia the antennas 234 a through 234 t, respectively.

At the UE 115, the antennas 252 a through 252 r may receive the downlinksignals from the base station 105 and may provide received signals tothe demodulators (DEMODs) 254 a through 254 r, respectively. Eachdemodulator 254 may condition (e.g., filter, amplify, downconvert, anddigitize) a respective received signal to obtain input samples. Eachdemodulator 254 may further process the input samples (e.g., for OFDM,etc.) to obtain received symbols. A MIMO detector 256 may obtainreceived symbols from all the demodulators 254 a through 254 r, performMIMO detection on the received symbols if applicable, and providedetected symbols. A receive processor 258 may process (e.g., demodulate,deinterleave, and decode) the detected symbols, provide decoded data forthe UE 115 to a data sink 260, and provide decoded control informationto a controller/processor 280.

On the uplink, at the UE 115, a transmit processor 264 may receive andprocess data (e.g., for the PUSCH) from a data source 262 and controlinformation (e.g., for the PUCCH) from the controller/processor 280. Thetransmit processor 264 may also generate reference symbols for areference signal. The symbols from the transmit processor 264 may beprecoded by a TX MIMO processor 266 if applicable, further processed bythe modulators 254 a through 254 r (e.g., for SC-FDM, etc.), andtransmitted to the base station 105. At the base station 105, the uplinksignals from the UE 115 may be received by the antennas 234, processedby the demodulators 232, detected by a MIMO detector 236 if applicable,and further processed by a receive processor 238 to obtain decoded dataand control information sent by the UE 115. The processor 238 mayprovide the decoded data to a data sink 239 and the decoded controlinformation to the controller/processor 240.

The controllers/processors 240 and 280 may direct the operation at thebase station 105 and the UE 115, respectively. The controller/processor240 and/or other processors and modules at the base station 105 mayperform or direct the execution of various processes for the techniquesdescribed herein. The controllers/processor 280 and/or other processorsand modules at the UE 115 may also perform or direct the execution ofthe functional blocks illustrated in FIGS. 4A and 4B, and/or otherprocesses for the techniques described herein. The memories 242 and 282may store data and program codes for the base station 105 and the UE115, respectively. A scheduler 244 may schedule UEs for datatransmission on the downlink and/or uplink.

Wireless communications systems operated by different network operatingentities (e.g., network operators) may share spectrum. In someinstances, a network operating entity may be configured to use anentirety of a designated shared spectrum for at least a period of timebefore another network operating entity uses the entirety of thedesignated shared spectrum for a different period of time. Thus, inorder to allow network operating entities use of the full designatedshared spectrum, and in order to mitigate interfering communicationsbetween the different network operating entities, certain resources(e.g., time) may be partitioned and allocated to the different networkoperating entities for certain types of communication.

For example, a network operating entity may be allocated certain timeresources reserved for exclusive communication by the network operatingentity using the entirety of the shared spectrum. The network operatingentity may also be allocated other time resources where the entity isgiven priority over other network operating entities to communicateusing the shared spectrum. These time resources, prioritized for use bythe network operating entity, may be utilized by other network operatingentities on an opportunistic basis if the prioritized network operatingentity does not utilize the resources. Additional time resources may beallocated for any network operator to use on an opportunistic basis.

Access to the shared spectrum and the arbitration of time resourcesamong different network operating entities may be centrally controlledby a separate entity, autonomously determined by a predefinedarbitration scheme, or dynamically determined based on interactionsbetween wireless nodes of the network operators.

In some cases, UE 115 and base station 105 may operate in a shared radiofrequency spectrum band, which may include licensed or unlicensed (e.g.,contention-based) frequency spectrum. In an unlicensed frequency portionof the shared radio frequency spectrum band, UEs 115 or base stations105 may traditionally perform a medium-sensing procedure to contend foraccess to the frequency spectrum. For example, UE 115 or base station105 may perform a listen before talk (LBT) procedure such as a clearchannel assessment (CCA) prior to communicating in order to determinewhether the shared channel is available. A CCA may include an energydetection procedure to determine whether there are any other activetransmissions. For example, a device may infer that a change in areceived signal strength indicator (RSSI) of a power meter indicatesthat a channel is occupied. Specifically, signal power that isconcentrated in a certain bandwidth and exceeds a predetermined noisefloor may indicate another wireless transmitter. A CCA also may includedetection of specific sequences that indicate use of the channel. Forexample, another device may transmit a specific preamble prior totransmitting a data sequence. In some cases, an LBT procedure mayinclude a wireless node adjusting its own backoff window based on theamount of energy detected on a channel and/or theacknowledge/negative-acknowledge (ACK/NACK) feedback for its owntransmitted packets as a proxy for collisions.

Use of a medium-sensing procedure to contend for access to an unlicensedshared spectrum may result in communication inefficiencies. This may beparticularly evident when multiple network operating entities (e.g.,network operators) are attempting to access a shared resource. In 5Gnetwork 100, base stations 105 and UEs 115 may be operated by the sameor different network operating entities. In some examples, an individualbase station 105 or UE 115 may be operated by more than one networkoperating entity. In other examples, each base station 105 and UE 115may be operated by a single network operating entity. Requiring eachbase station 105 and UE 115 of different network operating entities tocontend for shared resources may result in increased signaling overheadand communication latency.

FIG. 3 illustrates an example of a timing diagram 300 for coordinatedresource partitioning. The timing diagram 300 includes a superframe 305,which may represent a fixed duration of time (e.g., 20 ms). Superframe305 may be repeated for a given communication session and may be used bya wireless system such as 5G network 100 described with reference toFIG. 1. The superframe 305 may be divided into intervals such as anacquisition interval (A-INT) 310 and an arbitration interval 315. Asdescribed in more detail below, the A-INT 310 and arbitration interval315 may be subdivided into sub-intervals, designated for certainresource types, and allocated to different network operating entities tofacilitate coordinated communications between the different networkoperating entities. For example, the arbitration interval 315 may bedivided into a plurality of sub-intervals 320. Also, the superframe 305may be further divided into a plurality of subframes 325 with a fixedduration (e.g., 1 ms). While timing diagram 300 illustrates threedifferent network operating entities (e.g., Operator A, Operator B,Operator C), the number of network operating entities using thesuperframe 305 for coordinated communications may be greater than orfewer than the number illustrated in timing diagram 300.

The A-INT 310 may be a dedicated interval of the superframe 305 that isreserved for exclusive communications by the network operating entities.In some examples, each network operating entity may be allocated certainresources within the A-INT 310 for exclusive communications. Forexample, resources 330-a may be reserved for exclusive communications byOperator A, such as through base station 105 a, resources 330-b may bereserved for exclusive communications by Operator B, such as throughbase station 105 b, and resources 330-c may be reserved for exclusivecommunications by Operator C, such as through base station 105 c. Sincethe resources 330-a are reserved for exclusive communications byOperator A, neither Operator B nor Operator C can communicate duringresources 330-a, even if Operator A chooses not to communicate duringthose resources. That is, access to exclusive resources is limited tothe designated network operator. Similar restrictions apply to resources330-b for Operator B and resources 330-c for Operator C. The wirelessnodes of Operator A (e.g, UEs 115 or base stations 105) may communicateany information desired during their exclusive resources 330-a, such ascontrol information or data.

When communicating over an exclusive resource, a network operatingentity does not need to perform any medium sensing procedures (e.g.,listen-before-talk (LBT) or clear channel assessment (CCA)) because thenetwork operating entity knows that the resources are reserved. Becauseonly the designated network operating entity may communicate overexclusive resources, there may be a reduced likelihood of interferingcommunications as compared to relying on medium sensing techniques alone(e.g., no hidden node problem). In some examples, the A-INT 310 is usedto transmit control information, such as synchronization signals (e.g.,SYNC signals), system information (e.g., system information blocks(SIBs)), paging information (e.g., physical broadcast channel (PBCH)messages), or random access information (e.g., random access channel(RACH) signals). In some examples, all of the wireless nodes associatedwith a network operating entity may transmit at the same time duringtheir exclusive resources.

In some examples, resources may be classified as prioritized for certainnetwork operating entities. Resources that are assigned with priorityfor a certain network operating entity may be referred to as aguaranteed interval (G-INT) for that network operating entity. Theinterval of resources used by the network operating entity during theG-INT may be referred to as a prioritized sub-interval. For example,resources 335-a may be prioritized for use by Operator A and maytherefore be referred to as a G-INT for Operator A (e.g., G-INT-OpA).Similarly, resources 335-b may be prioritized for Operator B, resources335-c may be prioritized for Operator C, resources 335-d may beprioritized for Operator A, resources 335-e may be prioritized forOperator B, and resources 335-f may be prioritized for operator C.

The various G-INT resources illustrated in FIG. 3 appear to be staggeredto illustrate their association with their respective network operatingentities, but these resources may all be on the same frequencybandwidth. Thus, if viewed along a time-frequency grid, the G-INTresources may appear as a contiguous line within the superframe 305.This partitioning of data may be an example of time divisionmultiplexing (TDM). Also, when resources appear in the same sub-interval(e.g., resources 340-a and resources 335-b), these resources representthe same time resources with respect to the superframe 305 (e.g., theresources occupy the same sub-interval 320), but the resources areseparately designated to illustrate that the same time resources can beclassified differently for different operators.

When resources are assigned with priority for a certain networkoperating entity (e.g., a G-INT), that network operating entity maycommunicate using those resources without having to wait or perform anymedium sensing procedures (e.g., LBT or CCA). For example, the wirelessnodes of Operator A are free to communicate any data or controlinformation during resources 335-a without interference from thewireless nodes of Operator B or Operator C.

A network operating entity may additionally signal to another operatorthat it intends to use a particular G-INT. For example, referring toresources 335-a, Operator A may signal to Operator B and Operator C thatit intends to use resources 335-a. Such signaling may be referred to asan activity indication. Moreover, since Operator A has priority overresources 335-a, Operator A may be considered as a higher priorityoperator than both Operator B and Operator C. However, as discussedabove, Operator A does not have to send signaling to the other networkoperating entities to ensure interference-free transmission duringresources 335-a because the resources 335-a are assigned with priorityto Operator A.

Similarly, a network operating entity may signal to another networkoperating entity that it intends not to use a particular G-INT. Thissignaling may also be referred to as an activity indication. Forexample, referring to resources 335-b, Operator B may signal to OperatorA and Operator C that it intends not to use the resources 335-b forcommunication, even though the resources are assigned with priority toOperator B. With reference to resources 335-b, Operator B may beconsidered a higher priority network operating entity than Operator Aand Operator C. In such cases, Operators A and C may attempt to useresources of sub-interval 320 on an opportunistic basis. Thus, from theperspective of Operator A, the sub-interval 320 that contains resources335-b may be considered an opportunistic interval (O-INT) for Operator A(e.g., O-INT-OpA). For illustrative purposes, resources 340-a mayrepresent the O-INT for Operator A. Also, from the perspective ofOperator C, the same sub-interval 320 may represent an O-INT forOperator C with corresponding resources 340-b. Resources 340-a, 335-b,and 340-b all represent the same time resources (e.g., a particularsub-interval 320), but are identified separately to signify that thesame resources may be considered as a G-INT for some network operatingentities and yet as an O-INT for others.

To utilize resources on an opportunistic basis, Operator A and OperatorC may perform medium-sensing procedures to check for communications on aparticular channel before transmitting data. For example, if Operator Bdecides not to use resources 335-b (e.g., G-INT-OpB), then Operator Amay use those same resources (e.g., represented by resources 340-a) byfirst checking the channel for interference (e.g., LBT) and thentransmitting data if the channel was determined to be clear. Similarly,if Operator C wanted to access resources on an opportunistic basisduring sub-interval 320 (e.g., use an O-INT represented by resources340-b) in response to an indication that Operator B was not going to useits G-INT, Operator C may perform a medium sensing procedure and accessthe resources if available. In some cases, two operators (e.g., OperatorA and Operator C) may attempt to access the same resources, in whichcase the operators may employ contention-based procedures to avoidinterfering communications. The operators may also have sub-prioritiesassigned to them designed to determine which operator may gain access toresources if more than operator is attempting access simultaneously.

In some examples, a network operating entity may intend not to use aparticular G-INT assigned to it, but may not send out an activityindication that conveys the intent not to use the resources. In suchcases, for a particular sub-interval 320, lower priority operatingentities may be configured to monitor the channel to determine whether ahigher priority operating entity is using the resources. If a lowerpriority operating entity determines through LBT or similar method thata higher priority operating entity is not going to use its G-INTresources, then the lower priority operating entities may attempt toaccess the resources on an opportunistic basis as described above.

In some examples, access to a G-INT or O-INT may be preceded by areservation signal (e.g., request-to-send (RTS)/clear-to-send (CTS)),and the contention window (CW) may be randomly chosen between one andthe total number of operating entities.

In some examples, an operating entity may employ or be compatible withcoordinated multipoint (CoMP) communications. For example an operatingentity may employ CoMP and dynamic time division duplex (TDD) in a G-INTand opportunistic CoMP in an O-INT as needed.

In the example illustrated in FIG. 3, each sub-interval 320 includes aG-INT for one of Operator A, B, or C. However, in some cases, one ormore sub-intervals 320 may include resources that are neither reservedfor exclusive use nor reserved for prioritized use (e.g., unassignedresources). Such unassigned resources may be considered an O-INT for anynetwork operating entity, and may be accessed on an opportunistic basisas described above.

In some examples, each subframe 325 may contain 14 symbols (e.g., 250-μsfor 60 kHz tone spacing). These subframes 325 may be standalone,self-contained Interval-Cs (ITCs) or the subframes 325 may be a part ofa long ITC. An ITC may be a self-contained transmission starting with adownlink transmission and ending with a uplink transmission. In someembodiments, an ITC may contain one or more subframes 325 operatingcontiguously upon medium occupation. In some cases, there may be amaximum of eight network operators in an A-INT 310 (e.g., with durationof 2 ms) assuming a 250-μs transmission opportunity.

Although three operators are illustrated in FIG. 3, it should beunderstood that fewer or more network operating entities may beconfigured to operate in a coordinated manner as described above. Insome cases, the location of the G-INT, O-INT, or A-INT within superframe305 for each operator is determined autonomously based on the number ofnetwork operating entities active in a system. For example, if there isonly one network operating entity, each sub-interval 320 may be occupiedby a G-INT for that single network operating entity, or thesub-intervals 320 may alternate between G-INTs for that networkoperating entity and O-INTs to allow other network operating entities toenter. If there are two network operating entities, the sub-intervals320 may alternate between G-INTs for the first network operating entityand G-INTs for the second network operating entity. If there are threenetwork operating entities, the G-INT and O-INTs for each networkoperating entity may be designed as illustrated in FIG. 3. If there arefour network operating entities, the first four sub-intervals 320 mayinclude consecutive G-INTs for the four network operating entities andthe remaining two sub-intervals 320 may contain O-INTs. Similarly, ifthere are five network operating entities, the first five sub-intervals320 may contain consecutive G-INTs for the five network operatingentities and the remaining sub-interval 320 may contain an O-INT. Ifthere are six network operating entities, all six sub-intervals 320 mayinclude consecutive G-INTs for each network operating entity. It shouldbe understood that these examples are for illustrative purposes only andthat other autonomously determined interval allocations may be used.

It should be understood that the coordination framework described withreference to FIG. 3 is for illustration purposes only. For example, theduration of superframe 305 may be more or less than 20 ms. Also, thenumber, duration, and location of sub-intervals 320 and subframes 325may differ from the configuration illustrated. Also, the types ofresource designations (e.g., exclusive, prioritized, unassigned) maydiffer or include more or less sub-designations.

In communications over a shared communication medium, both sharedbetween communicating entities operated by the same network operator andentities between different network operators vying for resources on theshared medium, a coordinated window may be defined for providing controlsignaling and potentially high priority traffic. Such a window may bereferred to herein as a Discovery Measurement and Timing Configuration(DMTC) window. As noted, control signaling and potentially high prioritytraffic can be transmitted in prioritized manner within the DMTC window.

In order to establish or re-establish communication with a new cell, aUE transmits random access signals using the random access channel(RACH) on the physical random access channel (PRACH). With PRACH, boththe UE and base station may be in synchronization with the resourcesused and the order of the scanning of beams. The PRACH configuration maybe given in system information. However, if PRACH resources are allowedto float and follow NR synchronization signals, a PRACH offset from thebeginning of the DMTC window would be indicated in the physicalbroadcast channel (PBCH)/master information block (MIB). Since NRsynchronization signals are subject to listen before talk (LBT)procedures, PRACH transmissions may also be subject to LBT procedures.If NR synchronization signals are not subject to LBT procedures, PRACHcan simply follow NR synchronization signals and not be subject to LBT.

FIGS. 4A and 4B are block diagrams illustrating example blocks accordingto one aspect of the present disclosure. The example blocks of FIG. 4Awill also be described with respect to base station 105 as illustratedin FIG. 8. FIG. 8 is a block diagram illustrating base station 105configured according to one aspect of the present disclosure. Basestation 105 includes the structure, hardware, and components asillustrated for base station 105 of FIG. 2. For example, base station105 includes controller/processor 240, which operates to execute logicor computer instructions stored in memory 242, as well as controllingthe components of base station 105 that provide the features andfunctionality of base station 105. Base station 105, under control ofcontroller/processor 240, transmits and receives signals via wirelessradios 800 a-t and antennas 234 a-t. Wireless radios 800 a-t includesvarious components and hardware, as illustrated in FIG. 2 for basestation 105, including modulator/demodulators 232 a-t, MIMO detector236, receive processor 238, transmit processor 220, and TX MIMOprocessor 230.

At block 400, a base station performs an LBT procedure on a sharedcommunication channel at a beginning of a DMTC window. Thesynchronization signals of NR networks are subject to contention-basedaccess to the shared communication. Accordingly, prior to transmittingthe synchronization block, base station 105, under control ofcontroller/processor 240, will execute LBT procedure 801, stored inmemory 242. The execution environment of LBT procedure 801 allows forbase station 105 to monitor for detectable activity on the sharedcommunication channel, and, if no activity is detected, reservationsignals may obtain access to the shared communication channel.

At block 401, the base station transmits synchronization signals over aplurality of directional beams according to a predetermined sequence.For example, base station 105, under control of controller/processor240, executes synchronization signal generator 802 to generate varioussynchronization signals (e.g., primary synchronization signal (PSS),secondary synchronization signal (SSS), physical broadcast channel(PBCH), and the like). Base station 105 transmits the generatedsynchronization signals via wireless radios 800 a-t and antennas 234 a-tin a directional manner. Thus, base station 105 would generally transmitthe synchronization block on multiple directional beams. Base station105 transmits on the directional beams according to a particularpredetermined sequence. This sequence, beam sequence 803, stored inmemory 242, and used during transmission of the synchronization blockmay be obtained by the neighboring UEs, which will also use informationfrom the sequence for transmitting RACH.

At block 402, the base station signals configuration of additionalrandom access resources in response to the LBT procedure delaying beyondthe dedicated random access resources. In broadcasting systeminformation, base station 105 may broadcast dedicated RACH resources804, allocated by base station 105 and stored in memory 242. With thesynchronization signals being subject to contention access. Thetransmission of such signals may be delayed long enough to overlapdedicated random access resources 804 reserved within the DMTC window.Base station 105 signals configuration of additional random accessresources 805, allocated by base station and stored in memory 242, forinstance when the synchronization block transmission pushes into thededicated PRACH resources. Base station 105 transmits such additionalrandom access resources 805 via wireless radios 800 a-t and antennas 234a-t. This signaling of such configurations may occur dynamically, as thebase station detects the synchronization signal transmission causing thededicated PRACH resources to no longer be applicable, orsemi-statically, by using system information to allocate additionalPRACH resources when the delay of synchronization signal LBT causes aneed for new PRACH resources.

The configuration of the additional PRACH resources could be signaled insystem information. In a first option for transmitting configuration ofthe additional PRACH resources, the base station may trigger orconfigure the PRACH resources dynamically with a downlink controlchannel (e.g., downlink control information (DCI), physical downlinkcontrol channel (PDCCH), etc.). In a second option for transmittingconfiguration of the additional PRACH resources, the base station maytrigger or configure the PRACH resources dynamically with the PBCH/MIB.In a third option for transmitting configuration of the additional PRACHresources, the base station may trigger or configure the PRACH resourcessemi-statically with system information. For each such option, the basestation may schedule other traffic as an implementation.

At block 403, the base station monitors for random access signals fromeach direction according to the predetermined sequence corresponding tothe plurality of directional beams within the additional random accessresources. For example, base station 105, under control ofcontroller/processor 240, will scan the directional beams via antennas234 a-t and wireless radios 800 a-t for any RACH from neighboring UEsaccording to beam sequence 803 used to transmit the synchronizationblock.

The example blocks of FIG. 4B will also be described with respect to UE115 as illustrated in FIG. 9. FIG. 9 is a block diagram illustrating UE115 configured according to one aspect of the present disclosure. UE 115includes the structure, hardware, and components as illustrated for UE115 of FIG. 2. For example, UE 115 includes controller/processor 280,which operates to execute logic or computer instructions stored inmemory 282, as well as controlling the components of UE 115 that providethe features and functionality of UE 115. UE 115, under control ofcontroller/processor 280, transmits and receives signals via wirelessradios 900 a-r and antennas 252 a-r. Wireless radios 900 a-r includesvarious components and hardware, as illustrated in FIG. 2 for eNB 105,including modulator/demodulators 254 a-r, MIMO detector 256, receiveprocessor 258, transmit processor 264, and TX MIMO processor 266.

On the UE side, at block 404, a UE obtains a first location of regularrandom access resources on a shared communication channel. UE 115 wouldreceive signals via antennas 252 a-r and wireless radios 900 a-r anddecode those signals to detect the dedicated PRACH resources. UE 115would store the decoded information at dedicated RACH resources 901, inmemory 282. The dedicated PRACH resources may be identified inbroadcasted system information. For example, the dedicated PRACHresources located within the DMTC window may be identified using PBCH,MIB, or the like. Thus, UE 115 may receive such system information thatincludes the regular random access resources.

At block 405, the UE monitors for a plurality of synchronization signalswithin a DMTC window, wherein the plurality of synchronization signalsare received on a plurality of directional beams in a beam sequence. Asnoted in FIG. 4A, the base station transmits the synchronization blockover multiple different directional beams according to a predeterminedbeam sequence. UE 115, under control of controller/processor 280,monitors and detects the synchronization block on multiple directionalbeams via antennas 252 a-r and antennas 900 a-r. UE 115 may thendetermine a sequence according to how the synchronization block wasreceived. This sequence may then be stored at beam sequence 903 inmemory 282.

At block 406, the UE receives configuration of additional random accessresources outside of the DMTC window. UE 115 may receive and decodesignals via antennas 252 a-r and wireless radios 900 a-r. The decodedsignals are determined to be additional resources and stored atadditional RACH resources 904 in memory 282. Depending on the dynamic orsemi-static option used by the base station for transmitting theconfiguration of additional PRACH resources 904, UE 115 may eitherreceive the dynamic configuration of additional PRACH resources 904 viaDCI, PDCCH, PBCH, MIB, or the like, or may receive the semi-staticconfiguration of additional PRACH resources 904.

At block 407, the UE transmits a random access signal on one of theplurality of directional beams after completing a successful LBTprocedure on the shared communication channel, wherein the transmittingis performed according to the beam sequence on the additional randomaccess resources. When the transmission of the synchronization block bythe base station causes the dedicated PRACH resources to float over theallocated resources, the configuration of the additional PRACH resourcesallows UE 115 to perform RACH using the additional resources. As RACH issubject to contention access. UE 115, under control ofcontroller/processor 280, executes LBT procedure 905, stored in memory282. The execution environment of LBT procedure 905 allows for UE 115 tolisten for activity on the shared communication channel via antennas 252a-r and wireless radios 900 a-r. When no activity is detected, UE 115may provide signals to reserve the channel for its RACH. UE 115, undercontrol of controller/processor 280, executes RACH procedure 906 whichprovides for UE 115 to transmit its RACH on the directional beamcorresponding to its direction from the base station. The executionenvironment of RACH procedure 906 will cause UE 115 to transmit the RACHaccording to the beam sequence, from beam sequence 903, that itdetermined based on the monitoring of the synchronization signals.

FIG. 5 is a block diagram illustrating a base station 105 a and UE 115 aconfigured according to one aspect of the present disclosure. Asillustrated, RACH opportunities 502 and 506 within DTMC windows 500 and504, respectively. If the start of the synchronization signaltransmissions floats, but the RACH availability remains within DMTCwindow 500 or 504, the beginning point of the RACH resources may beindicated dynamically and either explicitly or implicitly. PBCH/MIB canbe used for that purpose. For example, base station 105 a performs anLBT procedure before transmission of the synchronization block in DMTCwindows 500 and 504. After successful completion of the LBT procedure,base station 105 a transmits the synchronization block at SS/SI/Page 501and 505. The LBT procedure did not push RACH opportunities 502 and 506outside of DMTC window 500 or 504. Base station 105 a may then signalthe PRACH resources within DMTC windows 500 and 504 via PBCH or MIB.Using this PRACH resource information, UE 115 a may then signal RACH atRACH opportunity 502 or 506. After DMTC windows 500 and 504, access tothe shared communication may occur in contention regions 503 and 507 viaregular contention with other neighboring transmitters attempting toaccess the shared communication channel.

FIG. 6 is a block diagram illustrating a base station 105 a and UE 115 aconfigured according to one aspect of the present disclosure. In theillustrated aspect, the LBT procedure of base station 105 a pushes theRACH opportunity outside of DMTC windows 600 and 604. Thus, during DMTCwindows 600 and 604, base station 105 a would only send thesynchronization block. An additional window of resources is configuredfor RACH outside DMTC windows 600 and 604. The additional PRACHresources in the described example occurs within an uplink access window602 or 606.

Access for RACH during uplink access windows 602 and 606 may be managedusing a CET or single CCA option based on the band requirements. If aCET option is used, the PRACH resources may be protected in the similarfashion as for the DMTC window. Base station 105 a may eitherdynamically or semi-statically schedule uplink access windows 602 and606 for UE 115 a. Contention regions 601, 603, 605, and 607 may then beused for data communication with a typical contention-based accessscheme, where base station 105 a and UE 115 a contend for access to theshared communication channel with other neighboring transmitters.

FIG. 7 is a block diagram illustrating a base station 105 a and UE 115 aconfigured according to one aspect of the present disclosure. Dedicatedrandom access channel (RACH) resources 702 and 706 can be configuredwithin DMTC widows 700 and 704. In addition, contention based resourcesfor RACH are configured outside DTMC within contention regions 703 and707. For example, base station 105 a performs an LBT procedure beforetransmission of the synchronization block. After successfully completingthe LBT procedure, base station 105 a transmits the synchronizationsignals at SS/SI/Page 701 and 705. If the LBT procedure pushes the RACHopportunity beyond dedicated RACH resources 702 and 706, UE 115 a mayuse available spectrum on the shared communication channel duringcontention periods 703 or 707 to transmit RACH. UE 115 a may performRACH when its serving base station is not utilizing the medium and thereare no other users of medium.

For example, when UE 115 a desires to perform RACH for base station 105a, UE 115 a receives the scheduling or trigger of additional PRACHresources within contention regions 703 and 707. During these regions,UE 115 a may perform an LBT to determine whether or not the sharedcommunication channel is occupied or not. If not, then UE 115 a performsRACH. On the base station side, if base station 105 a has scheduled datatransmissions in either of contention regions 703 and 707, base station105 a will transmit the data, but, when it is not transmitting the data,it will monitor for RACH from UEs over the multiple directional beamsaccording to the beam sequence it used for transmitting thesynchronization block.

It should be noted that contention between PRACH transmissions and dataare more likely when base station 105 a communicates the configurationof the additional PRACH resources either dynamically via a broadcastsignal, such as PBCH/MIB, or semi-statically with system information. Insuch cases, the additional PRACH resources are configured separatelyfrom any transmission schedule of base station 105 a. When base station105 a dynamically signals the configuration of the additional PRACHresources using a downlink control channel, then base station 105 awould be able to schedule for both the data transmission and the PRACHresources. In order to avoid collisions of data and RACH transmissions,base station 105 a may schedule the data and UE 115 a PRACHtransmissions on different frequency resources.

Those of skill in the art would understand that information and signalsmay be represented using any of a variety of different technologies andtechniques. For example, data, instructions, commands, information,signals, bits, symbols, and chips that may be referenced throughout theabove description may be represented by voltages, currents,electromagnetic waves, magnetic fields or particles, optical fields orparticles, or any combination thereof.

The functional blocks and modules in FIGS. 4A and 4B may compriseprocessors, electronics devices, hardware devices, electronicscomponents, logical circuits, memories, software codes, firmware codes,etc., or any combination thereof.

Those of skill would further appreciate that the various illustrativelogical blocks, modules, circuits, and algorithm steps described inconnection with the disclosure herein may be implemented as electronichardware, computer software, or combinations of both. To clearlyillustrate this interchangeability of hardware and software, variousillustrative components, blocks, modules, circuits, and steps have beendescribed above generally in terms of their functionality. Whether suchfunctionality is implemented as hardware or software depends upon theparticular application and design constraints imposed on the overallsystem. Skilled artisans may implement the described functionality invarying ways for each particular application, but such implementationdecisions should not be interpreted as causing a departure from thescope of the present disclosure. Skilled artisans will also readilyrecognize that the order or combination of components, methods, orinteractions that are described herein are merely examples and that thecomponents, methods, or interactions of the various aspects of thepresent disclosure may be combined or performed in ways other than thoseillustrated and described herein.

The various illustrative logical blocks, modules, and circuits describedin connection with the disclosure herein may be implemented or performedwith a general-purpose processor, a digital signal processor (DSP), anapplication specific integrated circuit (ASIC), a field programmablegate array (FPGA) or other programmable logic device, discrete gate ortransistor logic, discrete hardware components, or any combinationthereof designed to perform the functions described herein. Ageneral-purpose processor may be a microprocessor, but in thealternative, the processor may be any conventional processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

The steps of a method or algorithm described in connection with thedisclosure herein may be embodied directly in hardware, in a softwaremodule executed by a processor, or in a combination of the two. Asoftware module may reside in RAM memory, flash memory, ROM memory,EPROM memory, EEPROM memory, registers, hard disk, a removable disk, aCD-ROM, or any other form of storage medium known in the art. Anexemplary storage medium is coupled to the processor such that theprocessor can read information from, and write information to, thestorage medium. In the alternative, the storage medium may be integralto the processor. The processor and the storage medium may reside in anASIC. The ASIC may reside in a user terminal. In the alternative, theprocessor and the storage medium may reside as discrete components in auser terminal.

In one or more exemplary designs, the functions described may beimplemented in hardware, software, firmware, or any combination thereof.If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. Computer-readable media includes both computerstorage media and communication media including any medium thatfacilitates transfer of a computer program from one place to another.Computer-readable storage media may be any available media that can beaccessed by a general purpose or special purpose computer. By way ofexample, and not limitation, such computer-readable media can compriseRAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic diskstorage or other magnetic storage devices, or any other medium that canbe used to carry or store desired program code means in the form ofinstructions or data structures and that can be accessed by ageneral-purpose or special-purpose computer, or a general-purpose orspecial-purpose processor. Also, a connection may be properly termed acomputer-readable medium. For example, if the software is transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, or digital subscriber line (DSL), thenthe coaxial cable, fiber optic cable, twisted pair, or DSL, are includedin the definition of medium. Disk and disc, as used herein, includescompact disc (CD), laser disc, optical disc, digital versatile disc(DVD), floppy disk and blu-ray disc where disks usually reproduce datamagnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media.

As used herein, including in the claims, the term “and/or,” when used ina list of two or more items, means that any one of the listed items canbe employed by itself, or any combination of two or more of the listeditems can be employed. For example, if a composition is described ascontaining components A, B, and/or C, the composition can contain Aalone; B alone; C alone; A and B in combination; A and C in combination;B and C in combination; or A, B, and C in combination. Also, as usedherein, including in the claims, “or” as used in a list of itemsprefaced by “at least one of” indicates a disjunctive list such that,for example, a list of “at least one of A, B, or C” means A or B or C orAB or AC or BC or ABC (i.e., A and B and C) or any of these in anycombination thereof.

The previous description of the disclosure is provided to enable anyperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the generic principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Thus, the disclosure is not intended to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A method of wireless communication, comprising:performing, by a base station, a listen before talk (LBT) procedure on ashared communication channel at a beginning of a discovery measurementtiming configuration (DMTC) window; transmitting, by the base station,synchronization signals on the shared communication channel in responseto success of the LBT procedure, wherein the synchronization signals aretransmitted over a plurality of directional beams according to apredetermined sequence; signaling, by the base station, configuration ofadditional random access resources in response to the LBT proceduredelaying beyond dedicated random access resources; and monitoring, bythe base station, for random access signals from each directioncorresponding to the plurality of directional beams within theadditional random access resources, wherein the monitoring monitors theeach direction according to the predetermined sequence.
 2. The method ofclaim 1, wherein the signaling the configuration includes one of:dynamically signaling the configuration using a downlink controlchannel; dynamically signaling the configuration using a broadcastmessage; and semi-statically signaling the configuration using a systeminformation message.
 3. The method of claim 2, further including:transmitting, by the base station, a schedule for an uplink accesswindow to one or more served user equipments (UEs), wherein theconfiguration of the additional random access resources includes anoffset from the beginning of the DMTC window identifying a random accessopportunity within the uplink access window.
 4. The method of claim 1,further including: scheduling, by the base station, data transmission tooccur after the DMTC window; transmitting, by the base station, dataaccording to the scheduling, wherein the monitoring is performedaccording to the predetermined sequence when the base station is nottransmitting.
 5. The method of claim 4, wherein the scheduling includes:scheduling the data transmission on data transmission resources, whereinthe data transmission resources are at a different frequency from theadditional random access resources.
 6. A method of wirelesscommunication, comprising: obtaining, by a user equipment (UE), a firstlocation of dedicated random access resources on a shared communicationchannel; monitoring, by the UE, for a plurality of synchronizationsignals within a discovery measurement timing configuration (DMTC)window, wherein the plurality of synchronization signals are received ona plurality of directional beams in a beam sequence; receiving, by theUE, configuration of additional random access resources outside of theDMTC window; and transmitting, by the UE, a random access signal on oneof the plurality of directional beams after completing a successfullisten before talk (LBT) procedure on the shared communication channel,wherein the transmitting is performed according to the beam sequence onthe additional random access resources.
 7. The method of claim 6,wherein the receiving the configuration includes one of: dynamicallyreceiving the configuration via a downlink control channel; dynamicallyreceiving the configuration via a broadcast message; and semi-staticallyreceiving the configuration via a system information message.
 8. Themethod of claim 7, further including: receiving, by the UE, a schedulefor an uplink access window, wherein the configuration of the additionalrandom access resources includes an offset from a beginning of the DMTCwindow identifying a random access opportunity within the uplink accesswindow.
 9. The method of claim 8, further including one of: determining,by the UE, that a base station has secured communications on the sharedcommunication channel, wherein the transmitting is in response to thedetermining; or performing a clear channel assessment (CCA) check of theshared communication channel prior to the transmitting, wherein thetransmitting is in response to success of the CCA check.
 10. Anapparatus configured for wireless communication, the apparatuscomprising: at least one processor; and a memory coupled to the at leastone processor, wherein the at least one processor is configured: toperform, by a base station, a listen before talk (LBT) procedure on ashared communication channel at a beginning of a discovery measurementtiming configuration (DMTC) window; to transmit, by the base station,synchronization signals on the shared communication channel in responseto success of the LBT procedure, wherein the synchronization signals aretransmitted over a plurality of directional beams according to apredetermined sequence; to signal, by the base station, configuration ofadditional random access resources in response to the LBT proceduredelaying beyond dedicated random access resources; and to monitor, bythe base station, for random access signals from each directioncorresponding to the plurality of directional beams within theadditional random access resources, wherein the configuration of the atleast one processor to monitor monitors the each direction according tothe predetermined sequence.
 11. The apparatus of claim 10, wherein theconfiguration of the at least one processor to signal the configurationincludes configuration of the at least one processor to one of:dynamically signal the configuration using a downlink control channel;dynamically signal the configuration using a broadcast message; andsemi-statically signal the configuration using a system informationmessage.
 12. The apparatus of claim 11, further including configurationof the at least one processor to transmit, by the base station, aschedule for an uplink access window to one or more served userequipments (UEs), wherein the configuration of the additional randomaccess resources includes an offset from the beginning of the DMTCwindow identifying a random access opportunity within the uplink accesswindow.
 13. The apparatus of claim 10, further including configurationof the at least one processor: to schedule, by the base station, datatransmission to occur after the DMTC window; to transmit, by the basestation, data according to the configuration of the at least oneprocessor to schedule, wherein the configuration of the at least oneprocessor to monitor is performed according to the predeterminedsequence when the base station is not transmitting.
 14. The apparatus ofclaim 13, wherein the configuration of the at least one processor toschedule includes configuration to schedule the data transmission ondata transmission resources, wherein the data transmission resources areat a different frequency from the additional random access resources.15. An apparatus configured for wireless communication, the apparatuscomprising: at least one processor; and a memory coupled to the at leastone processor, wherein the at least one processor is configured: toobtain, by a user equipment (UE), a first location of dedicated randomaccess resources on a shared communication channel; to monitor, by theUE, for a plurality of synchronization signals within a discoverymeasurement timing configuration (DMTC) window, wherein the plurality ofsynchronization signals are received on a plurality of directional beamsin a beam sequence; to receive, by the UE, configuration of additionalrandom access resources outside of the DMTC window; and to transmit, bythe UE, a random access signal on one of the plurality of directionalbeams after completing a successful listen before talk (LBT) procedureon the shared communication channel, wherein the configuration of the atleast one processor to transmit is performed according to the beamsequence on the additional random access resources.
 16. The apparatus ofclaim 15, wherein configuration of the at least one processor to receivethe configuration includes configuration of the at least one processorto one of: dynamically receive the configuration via a downlink controlchannel; dynamically receive the configuration via a broadcast message;and semi-statically receive the configuration via a system informationmessage.
 17. The apparatus of claim 16, further including configurationof the at least one processor to receive, by the UE, a schedule for anuplink access window, wherein the configuration of the additional randomaccess resources includes an offset from a beginning of the DMTC windowidentifying a random access opportunity within the uplink access window.18. The apparatus of claim 17, further including configuration of the atleast one processor to one of: determine, by the UE, that a base stationhas secured communications on the shared communication channel, whereinconfiguration of the at least one processor to transmit is executed inresponse to results of the configuration of the at least one processorto determine; or perform a clear channel assessment (CCA) check of theshared communication channel prior to transmission, wherein theconfiguration of the at least one processor to transmit is executed inresponse to success of the CCA check.